Re: minor doc improvements

Neil Conway wrote:
> I've applied the attached patch to HEAD. It does the following:
>
> Add a few more cross-references where appropriate, add more text
> about the FROM clause and an example to the UPDATE reference page,
> and make a few other SGML tweaks.
>
> Suggestions for further improvement (for example, to the UPDATE ref
> page) are welcome.

ISTM that the linking changes you propose are stretching the semantics
of DocBook.  If you want to link, why not just use <link>.  By using
<xref> plus endterm you're doing the same thing indirectly and you rely
on the remote endterm having a sensible grammatical structure that fits
into the local sentence.